Plagued Cam bearing in distributor gear failures

Performance mods and Advanced Stroker discussion.
Demon_dusty
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Plagued Cam bearing in distributor gear failures

Post by Demon_dusty »

Up for discussion

My story of 3 engines.
1st built- 4.0 .040 over pistons, head work. Balanced.
Built in 2000, over the years it has had 3 different brands of cams, several distributors, and oil pumps.
I was fighting cam bearing failures and chewing up distributor gears.

This engine had a coyotes double roller timing set..
I finally gave up, and started with a different block and built a stroker.

2nd build- scat stroker rotating assembly, .030 over, blue printed & balanced, voodoo 702 cam, fresh head with seat pressures set to cam specs.
Engine ran strong, 14.2 quarter mile in a 4200lbxj
This engine destroyed the distributor in 5000 miles.
Also had a new double roller coyotes set.

3rd engine. This engine was built in between the above two.
4.9 stroker. 12 weight nitrated crank, 6.150 forged rod, custom pistons. 8.8:1 comp, hesco head, hesco turbo cam, the head was ported and set up from hesco.
I have a 76mm t4 turbo with water to air intercooler.
Dyno'd at 426whp/540wtq on a mustang Dyno.
I used at factory style timing set on this engine.
It was built, finish and running in 2016, I beat the piss out of this combo.
I pulled the distributor this summer just the check, perfect, like new condition.

If you made it through all that, I have two shit engines were the only common part is the aftermarket timing set.
Another with a factory set, running with twice the output flawlessly.

My question is..
The people having issues or not remember what timing set they had installed in their engine?

Might be a fluke, but my experiences have me thinking.
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SkylinesSuck
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Re: Plagued Cam bearing in distributor gear failures

Post by SkylinesSuck »

Starting since 2003'ish.....

The stock cam on my unopened 4.0 ate a lobe.

Replaced that with a crane cam and double roller timing set. That eventually ejected the dizzy into the bottom of the hood. Dizzy gear was worn. Also noticed a cam lobe was starting to go again.

Bought a Golen crate stroker (which has a double roller). Noticed worn dizzy gear at some point. Installed Hesco oil pump with oil squirter to lube the dizzy gear. Later replaced dizzy. It was a while ago so I don't remember details.

Golen crate stroker ate a lobe. Replaced with a Russ spec'd nitrided CompCam, rollmaster double roller, and P&P head. Not cam related, but that motor trashed the woodruff key and crank snout.

New motor is in the process of getting put together and installed including another rollmaster double roller timing set. Shit I hope I finally have some luck.
Demon_dusty
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Joined: January 10th, 2019, 6:00 pm
Stroker Displacement: 4.7 & 4.6
Vehicle Year: 1994
Vehicle Make: Jeep
Vehicle Model: Cherokee

Re: Plagued Cam bearing in distributor gear failures

Post by Demon_dusty »

I've never had issues with lobe failures, as of yet at least.

Sounding like your having lots of distributor problems also. I have a rollmaster I haven't tried yet.

I'm using 2 of the hesco pumps with the squirter. Didn't help the wear.

Out of the 3 engines, the 2 with double rollers have had major cam problems. I can't see why they would cause any problems?

I was hoping to get feed back on what people were using for timing sets and if they had failures or not. Possibly link something together to help everyone.

Or to find out if it's totally unrelated.
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SkylinesSuck
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Re: Plagued Cam bearing in distributor gear failures

Post by SkylinesSuck »

Are the oil pump high volume or pressure pumps?
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Cheromaniac
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Re: Plagued Cam bearing in distributor gear failures

Post by Cheromaniac »

I used the stock '94-'98 silent link timing set on my stroker and had zero issues. These timing sets are very reliable, aren't prone to stretch, and there really is no need for a double roller.
1992 XJ 4.6 I6 - 5MT - Stroker build-up, Stroker "recipes" Sold
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Demon_dusty
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Re: Plagued Cam bearing in distributor gear failures

Post by Demon_dusty »

The oil pumps.
The 1st 4.0 built had several different styles of pumps. All combinations I tried never helped.

The turbo stroker has hesco high volume with oil squirter. Still running strong after 3 years. (With stock style timing set)

The 2nd stroker also has hesco high volume oil pump with squirter also, chewed distributor gear off in 5000 miles. (Double roller set)
Demon_dusty
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Re: Plagued Cam bearing in distributor gear failures

Post by Demon_dusty »

Cheromaniac, thanks for the response.
Demon_dusty
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Re: Plagued Cam bearing in distributor gear failures

Post by Demon_dusty »

This is the same distributor.
One side unworn, 180° opposite it's destroyed.
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Demon_dusty
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Re: Plagued Cam bearing in distributor gear failures

Post by Demon_dusty »

180°
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SkylinesSuck
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Re: Plagued Cam bearing in distributor gear failures

Post by SkylinesSuck »

Now that is weird. How does that happen? Off-center dizzy?
Tolemar
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Re: Plagued Cam bearing in distributor gear failures

Post by Tolemar »

First post here I’m building a stroker and found this website to do some more research. I’ve built plenty of high horsepower blown big block Chevy‘s for boats and cars but this will be my first Straight six. I’ve also had distributor gear issues in my bigblocks I’ve built and I think it might be oil pressure related. Obviously more pressure equals more load on that gear. Maybe the excessive weight of the double roller timing chain contributes to the problem. Funny thing is I used a comp cams plastic distributor gear to fix the problem and thinner oil and it seemed to not have any more issues. Makes me wonder if not letting the engine warm up enough letting the oil get up to operating temp to avoid higher cold pressure might contribute also.
billy_bob2012
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Re: Plagued Cam bearing in distributor gear failures

Post by billy_bob2012 »

Well these engines are known to be hard on dizzys when stroked and ran hard. The fix i did is drill a hole in the block get a .010 orifice and plumed it into the oil system, that way the dizzy gear is oiled directly. I've had zero issues and I drive mine like a racecar.
OSR Development because goin fast is what we do.
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Re: Plagued Cam bearing in distributor gear failures

Post by 6TIME »

Curious, What oil pump and weight of oil were you running? I had similar wiped out cam bearing issues and we found upon inspection with a surface profilometer that the cam journals were not polished properly from the Lunati. We took the same cam after completely wiping out the front two bearings and had it micropolished. Reinstalled the same cam/lifters with new cam bearings and it ran 82k until I put a different cam profile in. The new cam was polished and it's been running good on the same bearings for almost 13k. Inspect your new cam journals before use! Many people pointed the finger at the factory spring/pin cam button and cam walk but that didn't quite make complete sense, so we kept it for the test. My machinist was adamant that it was the cam journal surface so we corrected only that first and it fixed the problem.
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Re: Plagued Cam bearing in distributor gear failures

Post by dwg86 »

Cam walk do to using an early model timing chain in a late model block. The cam pin and spring may not be long enough to keep the cam from walking. The later model timing chain cover doesn’t have the bump in it for the pin to ride on.
I’m assuming the engine that lasted used the stock timing chain and gears with the retaining plate. No cam walk, that’s why it lasted.
Tolemar
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Re: Plagued Cam bearing in distributor gear failures

Post by Tolemar »

Ok so what years are you consider late model block? I just pulled a 1999 wrangler block down I’m building a stroker with and it’s a retainer plate cam and the timing cover has a nipple cast in it. Funny thing is the numbers cast in block say it’s a 2000-2001 block but maybe that when they put that block in a Cherokee. I have a bullet racing can with a bolt and spring pin. I hope it will work.
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